JPS58934A - Preparation of ester - Google Patents

Abstract

PURPOSE:To prepare the titled compound, in a short time, by condensing the vapor containing produced water and alcohol and distilled from the reaction mixture of an organic carboxylic acid or its anhydride with an alcohol, under specific temperature condition, thereby removing the liquid produced by the reaction and reducing the concentration of water in the reaction liquid. CONSTITUTION:In the preparation of an ester by the reaction of an organic carboxylic acid or its anhydride with an alcohol, the vapor of the alcohol and by-produced water distilled out from the reactor is condensed at a temperature higher than the boiling point of water under the pressure in the reactor and lower than the boiling point of the alcohol, especially lower than the temperature at which >=90% of the charged alcohol is condensed, and the condensed liquid is recycled to the reactor. The above esterification reaction is preferably carried out in the presence of a catalyst such as sulfuric acid, p-toluenesulfonic acid, alumina and caustic soda, titanic acid, etc.

Description

[Detailed Description of the Invention] The present invention provides a method for producing an ester by reacting an organic carboxylic acid or its anhydride with an alcohol. In the step #Rk where ester is produced by the lower reaction ξ, it is necessary to continuously remove water generated from the reaction system as one reaction progresses.

In conventional methods, raw material alcohol is generally used in excess, and reaction product water is azeotropically distilled with the excess alcohol to form a reaction mixture, which is completely condensed in a condenser, resulting in a condensate. The method used was to separate the phases into an aqueous phase and an alcohol phase, and transfer only the alcohol phase to a reactor k11m. However, a considerable amount of water is dissolved in the alcohol obtained by this method, and in order to spin this, there is also a method of adding it as a carrier like a similar solvent to reduce the dissolution of water in the alcohol phase. It is not possible to completely prevent water reflux, and therefore the reaction rate is low at the end of the 4Hj esterification reaction, and it takes a long time to complete the reaction. This method provides a method for eliminating water reflux to the reactor and extremely reducing water reflux to the reactor.In a method for producing esters by reacting organic carboxylic acids or their anhydrides with alcohols, the reaction product water and alcohol-containing The reactor distillate leakage is condensed at a temperature higher than the boiling point of water and lower than the boiling point of alcohol at the internal pressure of the reaction system, and the obtained l! This is a method of returning 1111 to the reaction*. Examples of organic carboxylic acids or their anhydrides include phthalic acid, trimellitic acid, biomellitic acid, and aromatic carboxylic acids such as their anhydrides. It can also be applied to aliphatic carbons.

Also, alcohols that have a boiling point higher than water, such as alcohols that have a boiling point of 110°C or higher under snow pressure, are used exclusively, such as n-amyl alcohol, 1-amyl alcohol, hexyl alcohol, hexanol, and alcohol. Octyl alcohol, 2+ethylheisanol,
Examples include nonyl alcohol, decyl alcohol, etc.◎
The ester obtained from the present invention can be obtained by reacting the above-mentioned Shun with alcohol in an appropriate amount, and is an ester with a boiling point higher than that of water. The present invention can be applied to a platform for producing esters.In this case, the above-mentioned carboxylic acid or its anhydride and alcohol are reacted by a known method. Distilled alcohol and reaction product water t1 Reaction system internal pressure km = higher than the boiling point of water and lower than the boiling point of alcohol,
In particular, it condenses at a temperature lower than the temperature at which 90% or more of the charged alcohol condenses.
It is possible to significantly reduce the water content in l.

The 18th aspect of the present invention will be explained in more detail. The simplest embodiment of the invention is the 111th elongation.

Steam distilled from reactor 1 at ζ- passes through 2 and condenses 1111
8, and is cooled to a temperature higher than the boiling point of water and lower than the boiling point of alcohol, and the In liquid, which mainly consists of alcohol, reacts with 4 and reacts with water, and is then cooled to a temperature higher than the boiling point of water and lower than that of alcohol. Outer IEK# is issued. In Figure 2, two condensation units were installed to collect the alcohol escaping into the exhaust gas, and the steam that was not absorbed by the 11JII unit 8 was then passed through the 2nd IjC1l unit 6 to the 2nd IjC1l unit.・Fully coagulate in 4 chambers ζ−, pass 8 m waves through 7, separate in phase separator ・4 chambers ζ−, and react alcohol phase from 9−
Allow to cool, and then drain the aqueous phase from 10° to 10° C. If necessary, you may also return only the alcohol phase to the reactor after separating the aqueous phase.

Although the esterification reaction can be carried out without a catalyst, it is more advantageous to use a catalyst. It is possible to use acidic catalysts, amphoteric catalysts such as alumina and caustic soda, titanic acid, titanate esters, zinc salts, tin compounds, etc., and the addition amount is sufficient to be 5 weight or less based on the starting carboxylic acid.

The reaction temperature was 160°C in the reactor used for 5 tons of Shunsei catalyst.
The temperature below is preferably 0. If the temperature is higher than 140°C, the reaction solution may become colored. 110 to 250℃ or preferably @ll・℃ for a 1m non-touch pot or a pot using an intrinsic catalyst tube
Hereinafter, tl means that the reaction rate is much less than 25・℃ or more! The molar ratio of alcohol and carboxylic acid is so large that alcohol is over IH*, but 4H
It is preferable that the stoichiometric amount of the C layer is 10 or more. The reaction pressure is kept at reaction 11fK and reaction II) wave phase.
.

The pressure should be set so that excess alcohol flows out.

According to the present invention, most of the reaction waves generated as the esterification reaction progresses are removed, and the water concentration in the reaction waves can be kept low, thereby increasing the reaction rate and increasing the reaction rate compared to conventional methods. can be completed in a short time.

The method of the present invention can be carried out continuously or batchwise. In the following examples, parts are parts by weight. Example 1 and Comparative Example 1 2-ethylhexanol 15 oil, 7-talic acid mono-
1s-water S wave of paratoluenesulfonic acid of O, aS weight- is continuously supplied to the raw material liquid and the raw material liquid consisting of 2-ethylhexyl 2781B to a reactor as shown in Section 211IV:, and the stagnation period is 50 minutes, 14 (It''r! Reaction-only reaction-only primary condenser and secondary condenser temperature
It was kept at s°C and sOtlic.

The reactor pressure was set to 125 HP (absolute pressure) and 400 HP
The reaction rates were compared. The boiling point of water at 125mHP is 54°C, 400. For Hf, it is 8 parts C. ◎The reaction results are shown in Table 1.

Example 2 and Comparison 112 Anhydrous 7 Talken 14811. 540 m5 of a straight-chain metal alcohol having 7 to 9 carbon atoms, 1.28 g of caustic soda, and 1.2 parts of aluminum hydroxide were placed in a 2 m long conventional reactor, and an esterification reaction was carried out under atmospheric pressure in a fractional manner.

Table 2 shows the results of determining the reaction rate over time when the temperature of the primary condenser was maintained at -13-0°C and 90°C.

[Brief explanation of drawings]

Figures 1 and 2 show the reaction apparatus used in the method of the present invention. Patent applicant Mitsubishi Gas Chemical Co., Ltd. Representative Hibiki Aiyo Figure 1, L2 (2)

Claims (1)

[Claims] A method for producing esters by reacting organic carboxylic acids or their anhydrides with alcohols During busy periods, the reaction-produced steam containing reaction product water and alcohol is heated to a temperature higher than the point at which the internal pressure of the reaction system is heated to the point where the alcohol is heated. Preparation of esters At a temperature lower than the boiling point of 't', the resulting condensate Il is tossed into a reactor Kj [characteristic